Police have warned that there has been a sharp increase in mobile phone theft in London over the past two years, as thieves focus on high-end smartphones such as the iPhone 5 and Samsung Galaxy S3 that are now widely used.

The figures released by the Metropolitan Police Service (MPS) show there were just shy of 10,000 phone thefts in December 2012, up from 8,000 in December 2010.

The rise in thefts was also evidenced by the fact in a six-month period between April and September, 2012 a staggering 28,800 iPhones were reported stolen in London - the equivalent of 158 iPhones a day. Overall a total number of 56,680 mobiles were stolen during the period, equating to 341 phones per day.

The police warned that many thefts occur when victims are using their devices outside, whether texting, calling or browsing the web, and then have them snatched from their hands by people on bikes, as this footage shows:

The police also warned people to be wary outside Tube and train stations, as many people instinctively check their devices on exiting, which is where many criminals lie in wait.

To highlight this growing scourge to law-abiding smartphone users, the MPS is launching a new campaign to highlight the issue, with posters such as those above set to be displayed across the city to warn of the issue.

The news of the rise in thefts will be of concern to many firms too, with many employees now using their own devices as their primary work devices too, potentially putting corporate data at risk.

It underlines the fact that corporate data protection is of high importance for many firms, with 95 percent of V3 readers voting that "Ensuring data is protected when employees are using their own devices for work purposes" is their number one IT concern for 2013.

Microsoft has launched a new competition which could net one lucky app developer a spot in an upcoming Windows Phone ad.

The Windows Phone Next App Star contest will see developers compete with each other to find out who makes the best app in the Windows App Store. Winners will be decided based on a criteria which weighs both users ratings and app quality.

"Windows Phone Next App Star is our way of thanking our community of developers for creating such a great array of dynamic, exciting Windows Phone apps," said Microsoft's senior director of the Windows Phone App team Todd Brix in a blog post.

The contest will examine all apps from developers who want to take part. Redmond employees will work as judges for the competition. They will measure user ratings in conjunction with an examination of app quality to find the 64 best apps. The top 64 apps will be showcased and put up to against each other week-by-week in a public vote.

Microsoft competition could turn out to be PR boon for Windows Phone. The new mobile OS is still not competing with the likes of Android and iOS. A main issue for Windows Phone devices has been its lack of apps. At the very least, the competition will put a spotlight on the apps the mobile OS does have.